php session have to start but when it starts give exception

Question

i have a site, with many tabs , when i open any tab i want to get some data from session, but that data can't be got without session_start(); and when i put session_start() , an exception thrown tell me that the session is already starts

this is the exception

A session had already been started - ignoring session_start()

Answer 1

You should check to see if the session is set before starting the session.

if(!isset($_SESSION)){
    session_start();
}

Answer 2

You can begin with

if(!$_SESSION) {
    session_start();
}

or,

@session_start();

The "@" supresses errors.